Textile



United States Patent Gfifice 3,039,895 Patented June 19, 1962 3,039,895TEXTILE James P. Yuk, Waynesboro, Va., assignor to E. I. du Pont deNemours and Company, Wilmington, Del., a corporation of Delaware NoDrawing. Filed Mar. 29, 1960, Ser. No. 18,264 16 Claims. (Cl. 117138.8)

This invention relates to oiled elastic structures and in particular toelastic filaments of synthetic segmented elastomeric copolymers havingan oil-based lubricant thereon.

It is well known that an elastic filament made of rubber of of asegmented copolymer, e.g., of the spandex type, cannot be processed iffree of a lubricating finish. Such elastic fibers have a greatertendency than do hard fibers for cohesion of adjacent filaments of theyarn to one another and for sticking of the yarn to other surfaces,which causes erratic running tensions. Furthermore, it has beengenerally accepted that oils cannot be used to lubricate rubberfilaments because of the harmful effect of such oils on physicalproperties. Accordingly, a material such as talc is usually used forlubricating filaments made of rubber, and talc may be used to lubricatespandex filaments. For this application tale is usually applied to thefilaments from a slurry in water or in some organic liquid, e.g.,alcohol or acetone, which is not an oil.

The use of talc as a finishing agent for elastic filaments is attendantwith many disadvantages. Both in manufacturing and in processing atalc-coated filament, talc is spattered around the area in which theyarn is being processed and creates a housekeeping nuisance as well as adust hazard. Use of talc produces a package with very poor over-endtake-off properties. These are attributed to the cohesion of thefilaments within the package. The package must accordingly be rewound ora rolling takeofi must be used. Talc presents serious abrasion problems,both on spinning machines and on processing equipment. In knitting,latch needles and cylinder head dials are worn out quickly by theabrasive action of the talc, and the star-wheels of yarn-coveringmachines are similarly affected. Poor stability of the talc slurryprevents the uniform application of the finish, and the talc content ofelastic filaments may be subject to wide variation. Since the talcslurry usually contains a certain amount of water, a drying step isrequired, and the yarn must be wound on relatively expensive plasticcores.

In addition to talc, a great number of other lubricating materialscommonly used in textile processing have been tried; however, none haveproved to be fully satisfactory. Some are readily absorbed by theelastic filament and when applied in a suificient quantity to providelubricating properties exude excessively when the filament is elongatedunder tension. Others form films that provide satisfactory lubricationwhen only slight tensions are encountered but break down when thefilaments are elongated under higher tensions. Still others do notprovide emulsions, solutions, and dispersions which are stable.

It is, therefore, an object of this invention to provide an elasticfilament with a lubricating finish which may be processed withoutdifficulty. A more particular object of this invention is to provide anelastic filament with an oil finish which has good stability, does notdiscolor, prevents cohesion of filaments on a wound package, andprovides adequate frictional properties on the fiber when in a stretchedcondition. Another object is to provide an elastic filament with alubricating finish that afiords antistatic protection of the filament.Still another object is to provide a lubricated elastic filament whichis non-abrasive and non-irritating to the skin. A further object is toprovide elastic filaments with an oil finish that, for certain end uses,do not need to be scoured. Other objects will be apparent from thefollowing detailed description.

The objects of this invention are accomplished by providing an oiledelastic structure comprising a filament of a synthetic segmentedelastomeric copolymer having a substantially anhydrous lubricatingfinish comprising a textile oil having dispersed therein finely dividedparticles of a Group I, II or III metal salt of a higher fatty acid.

The segmented copolymer which makes up the elastic filament of thisinvention consists of segments of a highmelting, crystalline polymeralternating with segments of a low-melting, amorphous polymer. Thecrystalline highmelting segment may be derived from, for example, apolyurea, polyurethane, polyamide, bis-ureylene polymer, or polyester.The low-melting amorphous segment may be derived from, for example, apolyester, a polyether, or a hydrocarbon polymer. Polymers of thespandex type are illustrative of such a segmented copolymer.

The segmented copolymers described in several patents are useful in thepractice of this invention. Among these are U.S. Reissue Patents 24,689and 24,691, British Patent 779,054, French Patent 1,172,566, and U.S.Patents 2,929,801, 2,929,802, 2,929,803 and 2,929,804. As disclosed inthese references, such segmented copolymers when in filament formdisplay elongations at the break in excess of 200%, elastic recovery (ortensile recovery) above about and stress decays below about 20%. Theterms elastic recovery and stress decay are defined in U.S. Reissue24,689, now abandoned.

By the term textile oil is meant the organic liquids with which textilefibers are normally treated during processing, such liquids being ingeneral oils of low volatility that serve to lubricate the fibers, forinstance, tallows, naphthenic oil, sulfated or sulfonated oils, aromaticoils, paraifinic oils, and synthetic oils such as the silicones.

l fixtures of oils may be used if desired. For example, it has beenfound that the addition of a boundary lubricant to a mineral oil basereduces the tendency for cohesion of the filaments on a wound package inthe practice of this invention. Suitable boundary lubricants includebodied peanut oil, alkanolamine fatty acid condensates, and thepolyoxyalkylenes such as copolymers of ethylene oxide and propyleneoxide. When a boundary lubricant is employed in addition to the baseoil, it is preferred to employ in addition thereto a supplementary fluidlubricant which acts as a blending agent and a dispersing aid. Examplesof such supplementary fluid lubricant are acetylated castor oil and thelong-chain esters of sorbitan. Acetylated castor oil is a preferredsupplementary fluid lubricant.

I have discovered that textile oils make a satisfactory finish forelastic filaments from segmented copolymers only when there is dispersedin such oils essentially colorless, finely-divided soaps of certainmetals of Groups I, II, and III of the periodic table. Metals of GroupIa of the well-known Mendelyeevs Periodic Table are useful and includethose having atomic weights between about 7 and 133, i.e., lithium,sodium, potassium, rubidium, and cesium. Metals of Group H include thosehaving atomic weights between about 24 and 137, i.e., magnesium,calcium, strontium, barium, zinc, and cadmium. From Group III, aluminumwhich has an atomic weight of about 27 may be used.

The higher fatty acids are the C to C saturated and unsaturated fattyacids. The soap, which is the salt of these fatty acids, may beprepared, of course, from substituted acids such as ketoand hydroxyacids, for example, 4-keto-stearic acid or lZ-hydroxy stearic acid,instead of fatty acids, or in admixture therewith, if desired. In allcases, a fatty acid-metal combination is suitable if the resulting soapis essentially colorless and may be obtained in a finely divided state.Thus, with the metals indicated, any of the acids described above may beused, since these soaps are obtainable as finely divided particleswhich, as will appear more fully hereinafter, is critical to thepractice of this invention.

Representative examples of suitable soaps include sodium capra-te,sodium laura-te, sodium behenate, potassium oleate, potassium myristate,lithium stearate, lithium pal-mitate, zinc stearate, calcium oleate,magnesium lau rate, aluminum trioctoate, and aluminum distearate. Thepreferred soaps are those of the Group II metals, especially those ofzinc, calcium and magnesium. Magnesium stearate is particularlypreferred.

In the practice of this invention it is important that the particle sizeof the dispersed soaps be in a critical range. In particular, theaverage radius of the dispersed particle as determined by standard lightscattering methods should fall in the range 0.05 to microns. Preferably,the dispersed particles fall within the range 0.2 to 1.5 microns.

Since the particle size and amount of dispersed soap in the oil finishaffects the viscosity thereof, the upper limit of the soap content inthe finish is governed by the limit of a-practical working viscosity. Inorder to avoid possible gelling and viscosity differences, thedispersions should be prepared at room temperature and used at roomtemperature. Although viscosities as high as several poises may beemployed, a :low viscosity finish, i.e., less than about 70 centipoises,is generally preferred to be used with the elastic filaments fromsegmented copolymers. A minimum amount of dispersed soap is necessary toachieve the benefits of the present invention. This minimum quantity isabout 2% by weight of the finish. Accordingly, the oil finish of thisinvention contains approximately 2% to 20% by weight of dispersedsolids. The preferred compositions contain about 5% to 13% of dispersedsolids.

The finishes of this invention may be applied to elastic fibers in anyconvenient manner. In general, the finish may be applied by any of thestandard procedures such as by dipping, padding, or spraying. Runningyarns may be treated, for example, by spraying, or by passing themthrough baths or over wicks or other similar devices from which theypick up the finish. Passing the filaments over a roller which dips intoa trough containing the finish is a convenient method of application.When the finish is continuously applied to elastic fibers as they arebeing spun, the trough-roller apparatus is preferably located at a pointon the threadline just beyond the first driven feed roll which theelastic filaments contact after leaving the spinneret.

Ordinarily, an oiled elastic filament treated accor ing to the presentinvention will contain less than about by weight of the finish. It hasbeen found that the minimum amount of finish required to affordsufiicient protection to the yarn is about 3.5% by weight. The preferredminimum amount of finish is about 5% by weight, and the preferred amountof finish on an oiled elastic filament of this invention is in the rangeof 5% to 8%.

This invention will be further illustrated, but is not intended to belimited by, the following examples in which parts and percentages are byweight unless otherwise specified.

Example I Ninety-two (92) parts of polytetramethylene ether glycol(0.092 mol) of approximately 1000 molecular weight is reacted with 8parts of 2,4-tolylene diisocyanate (0.046 mol) under an atmosphere ofnitrogen for three hours at 80 C. The product of this reaction (40parts), having terminal hydroxyl groups, is reacted with 10 parts ofp,p'-methy1ene diphenyl diisocyanate for one hour at 80 C. The productof this reaction, having terminal isocyanate groups, is diluted with 25parts of N,N'-dimethylformamide. Fifteen parts of this solution is chainextended by addition to 0.165 part of hydrazine hydrate in 30 parts ofdimethylforniamide. The resulting solution of elastomeric polymercontains aproximately 20% solids, and has -a viscosity of 400 to 500poises at 30 C. To this solution are added a slurry of titanium dioxidein dimethylforma-mide and a solution ofpoly(N,N-diethyl-'beta-aminoethyl methacrylate) in dimethyl-formamidesuch that the final mixture contains 5% of each additive based on theelastomeric solids.

The foregoing mixture is heated to a temperature of 50 C. to 70 C. andspun as a l5-filament yarn into a dry spinning column heated withnitrogen at 250 C. At the bottom of the column, the filaments areallowed to come into contact and coalesce to give a monofilament ofabout 300 denier. Upon emergence from the column, the monofilament istreated with a finish having the following composition:

Percent Mineral oil (No. 50) 75 Blown peanut oil (viscosity 250centistokes) 5 Acetylated castor oil (Flexricin P8 10 Zinc stearate l0Trademark of Baker Castor Oil Company. When unwound from a bobbin, theoiled elastic filament shows substantially no tendency to stick toadjacent filamerits.

' Example 11 A finish having the following composition is applied to theas-spun untreated monofilaments of Example I:

Percent Mineral oil (No. 50)) 72 Acetylated castor oil (Flexricin P-8 10Blown peanut oil (viscosity 250 centistokes) 5 Magnesium stearate 13 Themonofilaments of the elastic yarn of Example I, upon emergence from thespinning column, are treated with an oil finish having the followingcomposition:

Percent Mineral oil (No. 50) 62 Acetylated, partially alcoholized castoroil (Flexricin 62* 15 Blown neats-foot oil (viscosity 300 centistokes) 5Copolymer of ethylene oxide and propylene oxide (Ucon LB358 Sorbitanethylene oxide distearate (G-1052 5 Zinc laurate 8 1 Trademark of BakerCastor Oil Company. Trademark of Carbide 8:: Carbon Chemical Company. 8Sold by Atlas Powder Company.

Results with the oiled elastic filament similar to those of Examples Iand II are obtained.

Example IV A finish having the following composition is applied to theas-spun untreated monofilaments of Example I:

Percent Mineral oil (No. 50) 75 Blown peanut oil (viscosity 250centistokes) 5 Acetylated castor oil (Flexricin P8 10 Sodium stearate l0'l'radeniark of Baker Castor Oil Company.

Results with the finished yarn are similar to those from Example I.

Example V A finish having the following composition is applied to theas-spun untreated monofilaments of Example I:

Percent Mineral oil (No. 50) 75 Blown peanut oil (viscosity 250centistokes) 5 Acetylated castor oil (Flexricin P-8 Aluminum distearate(Witco aluminum stearate 1 Trademark of Baker Castor Oil Company.

1! Sold by the Witco Chemical Co.

Results with the finished yarn are similar to those from Example I.

In all of the above examples, the metal salts are dispersed in the othercomponents of the finish, and the dispersed particles have an averageradius in the range 0.05 to 5 microns. The physical properties of theelastic yarn of the above examples are not adversely affected by thepresence of the oil finish. Tenacity, elongation, modulus, stress decay,and elastic or tensile recovery are measured and found to be essentiallyequal to the same properties of the identical elastic filament having atalc finish. Substantially similar results are obtained when a polyesteror N-alkylated polyurethane is substituted for the polyether in thepandex yarn of the examples. Substantially similar results are alsoobtained when a urea segment, urethane segment, or amide segment issubstituted for the bisureylene segment of the spandex yarn of theexamples.

The oiled elastic yarns of this invention may be used in both thecovered and uncovered states. Covered yarns of improved appearance canbe made with fewer breaks on the covering machine than with spandexyarns having a talc finish. Because of the more uniform finish content,

better lubrication and tension control in the yarns of this I invention,knitting can be done directly from the packages of the as-spun yarn,instead of rewinding, as is commonly done with yarns having a talcfinish. The yarns of this invention may be used to produce novel endproducts, for example, in the field of Raschel knitting, where the useof rubber filaments or spandex filaments having a talc finish isimpractical.

As pointed out hereinbefore, the use of a substantially anhydrous finishcomposition affords many advantages over finishes containing water.Thus, drying of spin packages is eliminated, paper cores may be usedinstead of the more expensive plastic cores, maintenance due to rustingis lessened, and housekeeping is simplified.

The oil-based finish of this invention has the added advantage that thedispersed soaps afford antistatic protection to the elastic filaments.In this respect, magnesium stearate is outstanding. Consequently, theuse of special antistatic agents in the practice of this invention isnot required. Moreover, the oiled elastic filaments are free ofobjectionable color. This freedom from undesirable color is important inmany of the applications for which the filaments of this invention aresuited.

In the above examples a monofilament yarn of large denier is formed bycoalescence of many smaller filaments before applying the oil-basedfinish to form the filaments of this invention. Alternatively,individual fine-denier filaments (for example, 6 denier or less) may befirst treated with the oil-based finish, then collected into acontinuous filament tow which may be cut into staple. The elasticfilaments of staple length are useful in the formation of elastic yarn.

The oiled elastic filaments of this invention are useful in a Widevariety of products in both the covered and uncovered state. Thefilaments of this invention find particular utility in foundationgarments, girdles, corsets, surgical hosiery, woven or knitted swimWear, socks and sock tops. The filaments are also useful in brassiers,suspenders, garters, slip tops, lingerie straps for slips andbrassieres, form fitting hosiery afterwelts, support hosiery, surgicalbandages and tapes, medical supports, panties,

waistbands, leg bands, wristlets and jacket trim, dresswear, rainwear,skirts, sweaters, belts, suits, coats, hats, slacks, pajamas, skindiving suits, leotards, athletic uniforms, polo shirts, ski clothing,golf jackets, golf balls, golf club mittens, gloves, sling shots, watchstraps, narrow tapes and webbings, braids, sewing thread, hairnets, chinstraps, shoe gores, shoe fabrics, carpets and rugs, furnitureupholstery, slip covers, automobile upholstery, mattress covers, fittedsheets and bedding, ticking and quilting fabric, laundry bags, cardtable covers, shock cord core, industrial belting, wire and cablejackets, antigravity suits, crash barriers, wall covering, tou-peebases, face masks, woven and nonwoven fabrics, felts, papers, bookcovers and jackets, coatings, protective coverings,

' swimming pool covers, flannels, and protective clothing.

The filaments of this invention may be blended with relativelynonelastic filaments, e.g., nylon and/or nonelastic filaments in thestretchy form for making a wide variety of elastic or stretchy productsincluding woven, knitted and nonwoven fabrics for use in universalfitting apparel, e.g., socks, stockings, elastic cuffs, actionsportswear, and others as listed hereinbefore; household products, e.g.,form-fitting upholstery; industrial products, e.g., woven and nonwovenfelts, synthetic leather, filter fabrics, stuffing material, boatcovers, balloon fabrics, sleeping bags, hammocks, automobile tops, andtarpaulins; and medical products, e.g., surgical stockings and splinttapes. The filaments of this invention can be employed in theaforementioned applications in the form of either continuous filamentsor as a blend of staple fibers, as appropriate.

This application is a continuation-in-part of copending US. applicationSerial Number 852,194, filed November 12, 1959, now abandoned.

As many widely different embodiments of this invention may be madewithout departing from the spirit and scope thereof, it is to beunderstood that this invention is not to be limited to the specificembodiments thereof except as defined in the appended claims.

I claim:

1. An oiled elastic structure comprising a filament of a syntheticsegmented elastomeric copolymer having thereon at least about 3.5% byweight of a substantially anhydrous lubricant, said lubricant comprisinga textile oil and from about 2% to about 20% by weight of finely dividedparticles of a metal salt of a fatty acid containing from about 8 toabout 22 carbon atoms, said metal being selected from the classconsisting of Group Ia metals having an atomic weight between about 7and 133, Group II metals having an atomic weight between about 24 and137, and a Group III metal having an atomic weight of about 27, saidparticles having an average radius in the range between 0.05 and 5microns.

2. The product of claim 1 wherein said lubricant contains from about 5%to about 13% by weight of said particles.

3. The product of claim 1 wherein said lubricant is present in an amountfrom about 5% to about 8% by weight of said filaments.

4. The product of claim 1 wherein said particles have an average radiusin the range from 0.2 to 1.5 microns.

5. The product of claim 1 wherein said salt is magnesium stearate.

6. The product of claim 1 wherein said filament is 9. spandex filament.

7. A filament of a synthetic segmented elastomeric copolyrner having alubricating finish thereon comprising from about 5% to about 13% of itsweight, said finish containing about 72% of a mineral oil, about 10%acetylated castor oil, about 5% bodied peanut oil, and about 13%magnesium stearate, said magnesium stearate being dispersed in saidlubricating finish in the form of finely divided particles having anaverage radius in the range between 0.05 and 5 microns.

8. The product of claim 7 wherein said filament is a spandex filament.

9. The product of claim 7 wherein said segmented elas tomeric copolymeris a segmented polyurethane having intralinear nitrogen-to-nitrogenbonds.

10. An oiled elastic structure comprising a filament of a syntheticsegmented elastomeric copolymer having thereon at least about 3.5% byweight of a substantially anhydrous lubricant, said lubricant comprisinga textile oil and from about 2% to about 20% by weight of finely dividedparticles of a colorless metal salt of a fatty acid containing fromabout 8 to about 22 carbon atoms, said metal having a valence notgreater than 3 and an atomic weight between about 7 and about 137, saidparticles having an average radius in the range between 0.05 and 5microns.

11. The product of claim 10 wherein said metal is sodium.

8 12. The product claim magnesium.

13. The product zinc. 14. The product calcium.

15. The product barium.

16. The product aluminum.

claim claim claim 1. 10 cam wherein said said

said

said

said

metal metal metal metal metal References Cited in the file of thispatent UNITED STATES PATENTS Sherman July 9, 1940 Licita et a1 Nov. 26,1940

1. AN OILED ELASTIC STRUCTURE COMPRISING A FILAMENT OF A SYNTHETICSEGMENTED ELASTOMERIC COPOLYMER HAVING THEREON AT LEAST ABOUT 3.5% BYWEIGHT OF A SUBSTANTIALLY ANHYDROUS LUBRICANT, SAID LUBRICANT COMPRISINGA TEXTILE OIL AND FROM ABOUT 2% TO ABOUT 20% BY WEIGHT OF FINELY DIVIDEDPARTICLES OF A METAL SALT OF A FATTY ACID CONTAINING FROM ABOUT 8 TOABOUT 22 CARBON ATOMS, SAID METAL BEING SELECTED FROM THE CLASSCONSISTING OF GROUP IA METALS HAVING AN ATOMIC WEIGHT BETWEEN ABOUT 7AND 133, GROUP 11 METALS HAVING AN ATOMIC WEIGHT BETWEEN ABOUT 24 AND137, AND A GROUP 111 METAL HAVING AN ATOMIC WEIGHT OF ABOUT 27, SAIDPARTICLES HAVING AN AVERAGE RADIUS IN THE RANGE BETWEEN 0.05 AND 5MICRONS.